Devices have been developed for creating oscillatory motion in phase opposition in dry shaving apparatus. For example, DE 1 151 307 A describes an oscillating armature drive for dry shaving apparatus with reciprocating working motion. The oscillating armature drive includes a U-shaped electromagnet formed fast with the housing of the shaving apparatus. Arranged in the proximity of the poles of the stationary electromagnet are a working armature and on either side of the working armature in mass symmetry a respective oscillatory compensating armature.
In operation, the working armature, which drives the shaving cutter, oscillates parallel to the pole faces of the electromagnet, and the compensating armatures perform an oscillatory motion in phase opposition.
Another example, DE 196 80 506 T1 discloses an electric shaving apparatus having a linear oscillating motor with a stationary electromagnet and several movable components that are set in oscillation in phase opposition to each other by means of the electromagnet. The electromagnet is fixedly screwed to the chassis of the shaving apparatus. The movable components are movably suspended on the chassis by means of a leaf spring. The leaf spring has a plurality of slits to enable the individual movable components to move in relatively opposing directions.